The invention relates to a wind turbine impeller assembly.
Wind turbines are common devices which traditionally consist of a rotating axis driven by an attached blade which converts the raw energy of wind into directional work. Prior to the development of the rotating axis, the blunt force of the wind was harnessed to motivate watercraft through the use of a sail. The wind power industry has developed novel ways to harness wind power by using a blade or impeller, which is a modification of the sail, to cause rotation of an attached axis which is used to perform useful work or to store energy until it is needed. The wind industry has expanded to build everything from small mast-borne, propeller driven generators and alternators for ancillary electrical power on watercraft to gigantic, highly sophisticated turbines which can produce in excess of one megawatt of electricity.
The common denominator in commercially viable modern wind power is the use of the horizontal axis wind turbine which pitches (yaws) into the prevailing wind direction. The pitching mechanism depends on the ability of the horizontal axis of turbine rotation to be longitudinally aligned with the direction of the wind, maximizing the circumference, and thus the cross-section of moving air intercepted by the blades radiating from the central axis. This requires horizontal axis wind turbines to pitch into the wind by self-determinant means such as a vane on an agricultural water pump mill or a sophisticated sensor which activates steering gears on commercial turbines.
The most similar existing embodiment to this invention is named an airfoil assembly, U.S. Pat. No. 6,983,223, having fins which camber in response to air pressure in one direction and blades which camber in two directions. The description of the embodiment states that the invention is intended to begin operation at low wind speeds. The airfoil assembly is designed to yaw, or pitch into the wind with the blades either up-wind or down-wind of the center vertical pivot. The airfoil assembly does not appear to have the ability to rotate in the same direction consistently regardless of wind direction without the benefit of a vertical axis of revolution or human manipulation of the blade fins.
The fixed horizontal axis-mounted wind turbine blade with an independently rotating, pressure cambered fin differs from the airfoil assembly in that the blades maintain a fixed plane of revolution about the primary axis of rotation. The tips of the fins attached to the blades rotate freely to either side of the plane of blade revolution depending on which side is the wind-source side of blade revolution. The primary horizontal axis of rotation of this invention does not need to change direction at any time in order to function as claimed, however, the invention could be fitted on to a base with a central vertical pivot and directional vane to yaw (revolve) 180 degrees in the horizontal plane with incident wind direction. This would increase yield while still benefiting from the independently cambering fins, as the device would still rotate in the same direction regardless of which side of the plane of blade revolution was upwind.